Integration of a Regional Component to the Galileo Global component - with demonstrations in Europe and China
Background & Objectives
Combining GPS and Galileo will provide the end users with better positioning accuracy and availability. SBAS-like augmentation corrections and integrity information will further improve the performance, not only in positioning accuracy and availability but also in integrity monitoring.
IRC2G will prototype a system which provides end-users with a combined GPS/Galileo positioning solution with SBAS-augmentations. The system has been demonstrated in both Europe and China.
The implementation of the project consists of the following major tasks:
- Prototyping a simple multi-constellation augmentation system based on EGNOS SIS and the simulated Galileo augmentation and integrity information. Two SBAS message streams have been generated in the project, one for GPS (based on EGNOS SIS), and the other for Galileo which was generated in the project.
- Simulating the Galileo orbit and raw measurements as well as the corresponding augmentation corrections and integrity information. The error models for the Galileo satellite orbits and clocks were developed in the project and applied to the simulated Galileo raw measurements, corrections and integrity information. The error models were derived by comparing the IGS precise orbits with the corresponding GPS ephemeris.
- Developing a GPS/Galileo combined positioning user terminal to explore the GPS/Galileo augmentation service. The user terminal supports positioning with measurements ranging from multiple GNSS constellations (e.g. GPS and Galileo); multi-constellation augmentations (SBAS-based); real-time GPS measurements and simulated Galileo data in RINEX format; user-configurable positioning modes with different combinations of ranging measurements (GPS or Galileo) and SBAS corrections, and data logging and replay for any positioning mode.
- Demonstrations were carried out in both Europe and China. For the demonstration in China, a simple CPF was developed. It utilised the IGS predicted orbits to estimate the satellite clock and orbit corrections and estimated the real-time ionospheric corrections.
The objective of the project is to prototype a system which provides end-users with a combined GPS/Galileo positioning solution with SBAS-based augmentations. It will demonstrate the concept of multi-constellation augmentation.
Work performed & results
The project has successfully prototyped a functional multi-constellation augmentation service. The implementation of the project covers the aspects of real-time data collections, real-time data processing, Galileo simulation, SBAS signal generations, dissemination of the SBAS signal over the Internet and the development of a pocket-sized PC-based user terminal for exploring the multi-constellation augmentation service. Field tests have been carried out in Helsinki (FI), Nottingham (UK) and Beijing (CN). The field tests have demonstrated the functionalities of the system, though the system is not advanced enough yet for a 24/7 operation. The system prototype is well suited for demonstrating the concept of multi-constellation augmentation.